A cell phone is the biggest invention of this century. It changed our lives dramatically and nothing is the same anymore. Especially combining computer and phone made such a different world for everyone. The reason for the invention was to help us communicating easily, but in my opinion it also causes us to cut off communication between people. First of all, we became virtual humans because we are constantly texting and using social media on our phones, we also start having virtual friends as well. Of course it’s easier to express our good or bad feelings without seeing each other, but we need to find out how healthy this is. Human beings needs to share emotions and learn how to communicate with each other as a human not as a robot in order to develop healthy relations in their lives. In addition, child development gets affected negatively. Nowadays, every kid has a cell phone even though they’re very young. They prefer to text to their friends or play with their phones. In reality, kids need to learn how to play and talk with their friends. This is the way how to learn sharing, how to learn to have a discussion and agreement. We get all this kinds of habits when we are young so it’s very important to put a limit of using the cell phone for our kids. It should also be noted that cell phones affect our health negatively as well. Studies show that electromagnetic waves cause disturbance in sleep, difficulty in concentration, fatigue, and headache. They increase the resting blood pressure and reduce the production of melatonin; also they are implicated in DNA strand breaks and it may cause lung cancer. Even though we are all aware of these negative sides we don’t know how we lived before cell phones. Definitely, it makes our lives easier. It’s easy to reach each other especially if you are far away from your parents and friends. However, we lived before cell phones; everybody found the way to see and to talk to each other and we had our meetings...

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...﻿Chapter 1
Cell Theory- in the 18th century, two scientists came up with the cell theory. Schleiden and Schwen.
3 corollaries of the cell theory:
-all cells are alike in chemical composition
-all cells store and process information in the same way
-all cells arise from other cell through cell division
5 types of different Microscopes
1. Light Microscope- produces 2-D image
Direct descendants of Hooks scope> take two lenses to a light source> used this to magnify images up to 1,000 fold.
2. Confocal Microscope- uses lenses& a light source> produces a 3-D image.
3. Fluorescence Microscope- 2-D or 3-D, allows us to visualize fluorescent dyes.
4. Transmission Electron Microscope- it shoots a bean of electrons through a sample, and it collects whatever passes through.
-It can do a million fold magnifications.
2-D images, visualize down to 2nm(nanometers)
1mm=1000mm(micrometers)
1mm=1000nm
5. Scanning Electron Microscope- Functions in a similar function to a transmission electron microscope> 3-D images, 3-20 nm in size.
What does it mean to be alive?
All living things are composed of cells.
CellCells are the basic unit of life. A small membrane enclosed unit with a concentrated aqueous solution of chemicals. It’s endowed with the ability to copy itself.
-Every living thing is composed of a colony of...

...its ability to function? Why or why not? (Hint: those buried deep in the cell probably do different things than those closer to the cell membrane).
Structure does not affect function of the cells, cells have a particular structure that enables them to carry out their function in the best way.
2. Draw a labeled diagram of a small section of the plasma membrane and briefly describe its structure and function.
3. Describe the difference between the animal and plant cells.
Plant Cells have cell walls, which makes them appear rectangular or square in shape, these structures are composed of cellulose, hemicellulose and other materials, plant cells have chlorophyll the light absorbing pigment required for photosynthesis.
Animal cells do not have cell walls they only have a cell membrane, this makes their shape round, they have lysosones which plants do not.
Both contain DNA unique to their species or type of plant.
4. Which of the following structures are present in both prokaryotic and eukaryotic cells?
Plasma Membrane- present in both cell types
Golgi Apparatus- not present in the prokaryotic cell, present in the eukaryotic cell
DNA- both have DNA
Lysosomes and peroxisomes- prokaryotic cells do not have either, eukaryotic...

...Bones support, move, and protect the body; they also give us our features. But without bone cells we would have no bones. Bone cells are the living units that make up your bones and keep them functioning. Bone cells have two major roles, which are the production of new bones and resorption or destruction of old bone. They also carry out other small roles. There are four main types of bone cells: Osteogenic, which are bonecells that respond to traumas, osteoblasts, which form bone matrix around themselves by laying down collagen fibers and depositing the hard mineral material, osteocytes, which respond to the bodies need for lower or higher circulating level of minerals contained in the bone and osteoclasts, which break down bone tissue.
Bone cell replacements have a turn over time of ten years in humans. The definition of turnover time is the renewal of the matrix and the bone cells. The matrix of bone cells is the “intercellular substance of bone, consisting of collagenous fibers, ground substance, and inorganic salts”(Bone Matrix, Par. 2). Inside the bone cells and all other cells are organelles. Organelles are tiny organs in the cell. The nucleus is a large, often spherical body and has many gates that are called nuclear pores. The nucleus serves, as the control center of the cell. Within the nucleus...

...The prokaryotic cell precedes any forms of Bacteria, Archaea, and eventually Eukaryotes by approximately two billion years. This cell was the original life form on the planet and represents the smallest and least complex of all organisms. Through the process of mutation and adaptation they were able to survive to evolve into our modern day Bacteria, Archaea, Fungi and Protists. These post organisms have benefited from their early ancestor, by way of Endosymbiosis. Intricate protest and fungi are also able to use these genetic and chemical changes to their advantage and are very successful organisms.
A prokaryote is a single celled organism that is lacking a nucleus, mitochondria, and other membrane bound organelles. So determining the phylogenetic relationships among the present-day domains of life, the Archaea, Bacteria, and Eukaryote, has been of central importance to the study of early cellular evolution. Primordial Earth was a harsh environment however two of the main domains of prokaryotes were able to form. Archaea and Bacteria have a few differences with respect to DNA transcription, translation, and replication. Apart from that however they are very similar. Bacteria are the more complex organism of the two and were eventually were put to further use in the evolutionary path of the eukaryotic cell.
The theorized course by which prokaryotes paved the way to the first eukaryotic cells is known as...

...1. Eukaryotic cells have a true nucleus, bound by a double membrane. Prokaryotic cells have no nucleus. The purpose of the nucleus is to sequester the DNA-related functions of the big eukaryotic cell into a smaller chamber, for the purpose of increased efficiency. This function is unnecessary for the prokaryotic cell, because its much smaller size means that all materials within the cell are relatively close together. Of course, prokaryotic cells do have DNA and DNA functions. Biologists describe the central region of the cell as its "nucleoid" (-oid=similar or imitating), because it's pretty much where the DNA is located. But note that the nucleoid is essentially an imaginary "structure." There is no physical boundary enclosing the nucleoid.
2. Eukaryotic DNA is linear; prokaryotic DNA is circular (it has no ends).
3. Eukaryotic DNA is complexed with proteins called "histones," and is organized into chromosomes; prokaryotic DNA is "naked," meaning that it has no histones associated with it, and it is not formed into chromosomes. Though many are sloppy about it, the term "chromosome" does not technically apply to anything in a prokaryotic cell. A eukaryotic cell contains a number of chromosomes; a prokaryotic cell contains only one circular DNA molecule and a varied assortment of much smaller circlets of DNA called "plasmids."...

...Cells are some of the smallest organisms around. All living things consist of cells, and yet they are invisible to the naked eye. Cells are the basic structural and functional units of life. Cells are made up of many different parts which allow them to function properly.
All cells are separated from their surrounding by a cell membrane. The cell membrane regulates what enters and leaves the cell and also aids in the protection and support of the cell. A cell membrane is similar to the walls surrounding your house.
In plants the cell membrane is surrounded by a cell wall. The cell wall is outside the cell membrane, and its purpose is to help the membrane protect and support the cell. Since the cell wall is very porous, water, oxygen, carbon dioxide, and other substances can pass through easily. A cell wall is similar to a fence around your house, because it helps protect other things from getting inside the cell.
In many cells there is a the nucleus, which was first described by Robert Brown. If a cell does or does not have a nucleus has been used by scientists to divide cells into two general categories. The two...

...The cell functions much in the way a city does. Although it may be an old analogy, it may be one of the best. Following is a list of cell parts and how their function is similar to functions of a city or town.
The cell membrane is the city limits of our city. Outside of the city limits, the local government has no jurisdiction, but inside those limits, people are subject to the “laws of the land”.
The nucleus – This is the place where direction is given and DNA is sent from. This would be the city government; the body of the city that makes rules and regulations for people to live by.
The nuclear envelope – City government needs a home and that is typically City Hall. It is simply the walls of the governing body. However small holes are in the nuclear envelope of a cell that allow for passage of information. In a city, if the information does not get out to the people, there is no point in having a governing body.
The chromatin represents actual laws being made at City Hall that dictate what may and may not go on in the city.
Ribosomes are the productive citizens who live in the city. There are many people in a city working, living, raising families, doing what they do. Ribosomes are the “busy” parts of a cell, producing and working and doing what they need to do (typically synthesizing proteins, often enzymes)
Rough ER – This is the homes and businesses of the city. This is...

...The CELL THEORY, or cell doctrine, states that all organisms are composed of similar units of organization, called cells. The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. The idea predates other great paradigms of biology including Darwin's theory of evolution (1859), Mendel's laws of inheritance (1865), and the establishment of comparative biochemistry (1940).
Ultrastructural research and modern molecular biology have added many tenets to the cell theory, but it remains as the preeminent theory of biology. The Cell Theory is to Biology as Atomic Theory is to Physics.
Formulation of the Cell Theory
In 1838, Theodor Schwann and Matthias Schleiden were enjoying after-dinner coffee and talking about their studies on cells. It has been suggested that when Schwann heard Schleiden describe plant cells with nuclei, he was struck by the similarity of these plant cells to cells he had observed in animal tissues. The two scientists went immediately to Schwann's lab to look at his slides. Schwann published his book on animal and plant cells (Schwann 1839) the next year, a treatise devoid of acknowledgments of anyone else's contribution, including that of Schleiden (1838). He summarized his observations into three conclusions about...